Project Summary Gastroesophageal reflux disease (GERD) is prevalent in USA and affects about 20% of the population and leads to decreased quality of life. If untreated, GERD can lead to complications such as esophagitis, Barrett?s esophagus and esophageal adenocarcinoma. Hiatal hernia is a condition in which the contents of the abdominal cavity, mainly the stomach, herniate through the hole meant for esophagus in the diaphragm and into the chest cavity. A strong link has been established between the presence of hiatal hernias and GERD. Moreover, presence of hiatal hernia doubles the risk of esophageal cancer. 85% of the hiatal hernia cases are of Type I and 5- 15% of the cases are of paraesophageal Type II-IV hernias, which when left untreated, apart from inducing GERD, can also result in ischemia or volvulus of the herniated contents. Laparoscopic hiatal hernia surgery is a minimally invasive procedure performed with specialized tools through five small incisions on the abdomen. It is an advanced general surgery procedure that has a learning curve of about 50 cases to achieve a low recurrent rate. Currently training for this procedure is through limited fellowships and there exists no animal, cadaver or virtual reality simulator to train in this specific procedure. Virtual reality simulators provide a standardized training environment where, a procedure can be practiced repeatedly to gain proficiency. They can also automatically assess the performance without any subjective influence. To address the gap in training for laparascopic hiatal hernia surgery, we propose to develop the Virtual Laparoscopic Hiatal Hernia Simulator (VLaHHS) with realistic modeling techniques, capabilities to simulate types III hiatal hernia, custom bimanual force feedback (haptic) interface. The VLaHHS developed in this project will also be useful to train surgeons in anti-reflux surgeries to treat GERD. We propose three specific aims to achieve and prove the effectiveness of our simulator. In aim1 we will develop the simulator that uses tissue properties and real-time deformation to simulate the procedure. We will develop custom haptic device to provide force feedback. In aim 2, we will develop, simulation scenario and metrics, and integrate into VLaHHS. In aim 3, we will conduct validation studies to prove that training on VLaHHS will lead to improved performance. The research will eventually lead to fewer surgical errors and improvement to patient safety.